Increasing the milk production of lactating dairy cattle, and meat production in cattle raised for meat, is an ongoing challenge to the farmer. It is possible to provide, or even exceed, the crude protein requirements of these animals when seeking higher milk or meat production. However, due to the nature of the ruminant digestive system, it may not be possible to “balance” the higher crude protein intake with essential amino acids or other biologically active substances required for the higher milk or meat output. Unfortunately, direct oral administration of the biologically active substances results in their being decomposed by the microorganisms present in the rumen, which is essentially a very efficient bioreactor.
More specifically, the digestive system of a ruminant animal originally evolved to allow it to benefit from feeds for which there was little competition from non-ruminants. In a ruminant, ingested feed is first chewed and then passes into the ruminant's four chambered “stomach.” The ruminant's four chambered “stomach” and their functions are now specifically considered. The first chamber, namely the reticulum, aids in bringing boluses of feed back to the mouth for rechewing. It is also kind of a “drop out box” for heavy objects that the animal may have ingested. The chewed, and rechewed feed then passes from the reticulum into the next chamber of the ruminant's stomach, called the rumen, where it is subjected to anaerobic fermentation. This microbial fermentation begins the digestive process and gives the ruminant the ability to utilize fibrous feeds that the mammalian system alone cannot break down due to the lack of necessary enzyme systems. The ruminant animal subsequently meets its nutrient needs by utilizing the by-products of this extensive fermentation, such as volatile fatty acids, along with any undigested feed residues and the resultant microbial mass that passes from the rumen. The normal pH of the rumen is 6 to 7. Once the feed has been reduced in size by chewing and digestion by the bacteria and protozoa in the rumen, it passes into the next compartment of the ruminant's stomach called the omasum. Also moving from the rumen to the omasum is a portion of the microbial mass that develops in the rumen. In addition, the omasum absorbs a large portion of the volatile fatty acids that move from the rumen to the omasum because they were not absorbed through the rumen wall. The omasum is also thought to absorb water and electrolytes such as potassium and sodium. The material in the omasum, then passes into the abomasum, the fourth, and final chamber of the ruminant's stomach. The abomasum is called the “true” stomach because it functions in a manner very similar to the stomach of a man or a pig. The walls of the abomasum secrete enzymes and hydrochloric acid. The pH of the digesta coming into the abomasum is about 6 to 7, but is quickly lowered to about 2.5 by the acid. This creates a proper environment for the enzymes to function. A primary digestive function of the abomasum is the partial breakdown of proteins. The enzyme pepsin is mainly responsible for protein breakdown. Proteins from the feed and the microorganism mass coming from the rumen are broken down into smaller units called peptides before leaving the abomasum.
The remaining parts of the ruminant digestive system, the small and large intestines, function just as they do in man or pig. In the upper half of the small intestine, digesta are further broken down, proteins into amino acids, starch to glucose, and complex fats into fatty acids. The amino acids, glucose and fatty acids are then absorbed in the lower half of the small intestine. The digesta leaving the small intestine enters the large intestine where water is absorbed, thus making the digesta more solid. Bacteria living in the large intestine work at digesting any feedstuffs which escaped digestion earlier. This usually contributes less than 15% of the total digestion. The final step in the ruminant digestive process is excretion from the large intestine.
As noted above, modern farmers seek to optimize milk and meat production by feeding the respective cattle an optimum diet. Providing sufficient crude protein in the diet is a relatively straight forward task. However, supplying sufficient quantities of essential amino acids to balance the crude protein intake and promote optimum milk and meat production has proved difficult or not possible. One of the reasons is the design of the ruminant digestive system, and in particular, the breakdown of amino acid compositions in the rumen prior to their reaching the abomasum and small intestine where these essential nutrients can be absorbed in the ruminant's small intestine.
The prior art discloses various ruminant feed compositions having biologically active substances useful in providing the desired amino acid to the ruminant which are said not to break down in the rumen and provide for release of the substance in the remaining stomachs of the ruminant. For example, U.S. Pat. No. 4,832,967 discloses a composition consisting of a biologically active substance which is stable in a medium whose pH is greater than 5 and which permits release of the substance in a medium whose pH is less than 3.5. This is said to be achieved using a precoating layer, a first coating layer sensitive to pH variations and a second coating layer of a hydrophobic substance.
Also known is U.S. Pat. No. 5,227,166 which discloses a composition consisting of a biologically active substance and a coating having lecithin, an inorganic substance which is stable under neutral conditions and a specific monocarboxylic acid having 14 to 22 carbon atoms, hardened vegetable oils, hardened animal oils and waxes.
Further known is U.S. Pat. No. 4,533,557 which discloses tablets or granules of a mixture of a biologically active substance, chitosan and protective materials of saturated or unsaturated aliphatic monocarboxylic acid having 14 to 22 carbon atoms, hardened vegetable oils and hardened animal oils. The chitosan is said to allow the biologically active substance of the composition to pass through the rumen and release in the abomasum.
Other prior art patents discuss additional compositions as ruminant feed additives including U.S. Pat. Nos. 3,541,204; 3,959,493; 4,595,584; 4,687,676; 4,877,621; 4,983,403; 5,616,339; 5,296,219, and 5,871,773.
In other fields it has also been recognized that fertilizer and pesticide products can be applied to a soil environment in order to control the release of the fertilizer or pesticide over a period of time. with respect to fertilizers, this permits a single application of the fertilizer which will last several months and possibly an entire growing season, avoiding the need for further applications. For example, U.S. Pat. Nos. 4,716,659; 4,804,403, and 4,969,947, assigned to the assignee of the present application, disclose an attritionresistant, controlled-release fertilizer comprising a water-soluble central mass, such as urea, containing nucleophilic reaction functional groups surrounding and chemically bonded to a base coating formed by reacting a molecular excess of a coupling agent, such as a polyisocyanate, with the nucleophilic groups of the central mass and a water-insoluble layer surrounding and chemically bonded with the base coating formed by the reaction and polymerization of the excess functional groups of the coupling agent. These products provide outstanding controlled-release fertilizer products. Similarly, U.S. Pat. No. 6,682,751, also assigned to the assignee of the present application, discloses a controlled release pesticide composition and method of making a controlled release pesticide composition providing outstanding controlled-release pesticide products.
These compositions and methods of the prior art ruminant feeds have various shortcomings including their efficiency in providing amino acid release in the abomasum, they are expensive and/or difficult to manufacture or simply can stand improvement. These and other shortcomings of these compositions and methods are addressed by the present invention.